Hemp (Cannabis sp.) has been a fundamental plant for the development of human societies. Its fibers have long been used for textiles and rope making, which requires prior stem retting. This process is essential for extracting fibers from the stem of the plant but can adversely affect the quality of surface waters. The history of human activities related to hemp (its domestication, spread, and processing) is frequently reconstructed from seeds and pollen detected in archaeological sites or in sedimentary archives, but this method does not always make it possible to ascertain whether retting took place. Hemp is also known to contain phytocannabinoids, a type of chemicals that is specific to the plant. One of these chemicals, cannabinol (CBN), was discovered in a sediment record from a lake in the French Massif Central and was shown to be related to retting. This molecule tracks the hemp retting history in the area during the last 800 years and brings information about its induced water pollution. These findings, supported by pollen analyses and historical data, show that this novel sedimentary tracer can help to better constrain past impacts of human activities on the environment.
Evidence for Hesperian glaciation along the Martian dichotomy boundary
Alfonso F. Davila et al., SETI Institute, Mountain View, California 94043, USA. Posted online ahead of print 9 May 2013; http://dx.doi.org/10.1130/G34201.1.
Alfonso F. Davila and colleagues analyzed images and topographic data from the Aeolis Mensae region of Mars. Their analyses indicate that these terrains were eroded by glacier
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Geological Society of America